1. Field of the Invention
This invention relates to a V-type split internal combustion engine operable on less than all of its cylinders when the engine load is below a given value and, more particularly, to an engine cooling system for use with such an engine.
2. Description of the Prior Art
It is known and desirable to increase the efficiency of a multicylinder internal combustion engine by reducing the number of cylinders on which the engine operates under predetermined engine operating conditions, particularly conditions of low engine load. For this purpose, control means has been provided which disables a number of cylinders in a multicylinder internal combustion engine by suppressing the supply of fuel to certain cylinders or by preventing the operation of the intake and exhaust valves of selected cylinders under low load conditions. The disablement of some of the cylinders of the engine increases the load on those remaining in operation and, as a result, the energy conversion efficiency is increased.
One difficulty with such a split internal combustion engine is the tendency toward an excessive reduction in the temperature of the cylinders disabled during a split engine mode of operation, causing unstable combustion therein when the engine operation is changed to its full engine mode and eventually misfiring therein particularly when the engine is accelerated after a relatively long period of a split engine mode of operation.
The present invention provides an engine cooling system for use in a V-type split internal combustion engine which can overcome any tendency toward an excessive reduction in the temperature of the cylinders disabled during a split engine mode of operation.